Fig. 2.

Composition and synthesis of thylakoid proteins in greenhouse-grown csp41 mutants and the WT. (A) Western analysis was performed on total protein extracts (40 μg) obtained from WT (Col-0) and mutant plants. Decreasing amounts of WT extract were added to lanes marked 0.75× Col-0 and 0.5× Col-0. Protein complexes were visualized and quantified using antibodies specific for representative subunits. Actin was used as a loading control. As a further control for loading, a replicate gel was stained with Coomassie brillant blue (C.B.B). One representative of three independently prepared immunoblots is shown. (B) Pulse labelling of thylakoid membrane proteins in young (7th–8th true) leaves and mature (3rd–4th true) leaves of WT and csp41 mutants. After inhibition of cytosolic translation with cycloheximide, plastid protein synthesis was monitored by pulse-labelling with [³⁵S]methionine for 20 min; thylakoid membrane proteins were isolated from WT and csp41 mutant leaves, fractionated by SDS–PAGE, and analysed by autoradiography. Prior to drying, the gel was stained with C.B.B. and the stained LHCII bands are indicated. The experiment was performed three times with similar results.